Field-programmable gate arrays (FPGAs) and programmable logic devices (PLDs) have been used in data communication and telecommunication systems. Conventional PLDs and FPGAs consist of an array of programmable elements, with the elements programmed to implement a fixed function or equation. Some currently-available Complex PLD (CPLD) products comprise arrays of logic cells. Conventional PLD devices have several drawbacks, such as high power consumption and large silicon area.
In developing complex electronic systems, there is often a need for additional peripheral units, such as operational and instrument amplifiers, filters, timers, digital logic circuits, analog to digital and digital to analog converters, etc. As a general rule, implementation of these extra peripherals creates additional difficulties: extra space for new components, additional attention during production of a printed circuit board, and increased power consumption. All of these factors can significantly affect the price and development cycle of the project.
The introduction of Programmable System on Chip (PSoC) chips feature digital and analog programmable blocks, which allow the implementation of a large number of peripherals. A programmable interconnect allows analog and digital blocks to be combined to form a wide variety of functional modules. The digital blocks consist of smaller programmable blocks and are configured to provide different digital functions. The analog blocks are used for development of analog elements, such as analog filters, comparators, inverting amplifiers, as well as analog to digital and digital to analog converters. Current PSoC architectures provide only a coarse grained digital programmability in which a few fixed functions with a small number of options are available.